The present invention relates generally to compositions and methods useful for determining the presence or absence of analytes, in particular, macromolecular analytes.
The clinical diagnostic field has seen a broad expansion over the years, both as to the variety of materials of interest that may be readily and accurately determined, as well as the methods for the determination. Convenient, reliable and non-hazardous means for detecting the presence of low concentrations of materials in liquids is desired. In clinical chemistry these materials may be present in body fluids in concentrations below 10−12 molar. The difficulty of detecting low concentrations of these materials is enhanced by the relatively small sample sizes that can be utilized.
Diseases such as, for example, an infectious disease or autoimmune disease, manifest in the formation of an antibody against a specific antigen that is characteristic of the disease and is found in the blood of a patient. It is, therefore, important in the detection of such diseases to detect the presence and/or amount of the antibody against a specific antigen characteristic of such disease. Samples such as blood, e.g., serum, typically have a myriad of antibodies present in the sample. Methods are known for detection of antibodies against specific antigens. Such methods involve binding, either non-covalently or covalently, all of the antibodies in a sample with a reagent and then identifying, from all of the bound antibodies, the antibody against the specific antigen. As a result a large amount of this reagent must be used because a majority of the reagent binds to antibodies that are not directed to the specific antigen of interest. Examples of such approaches include contacting a human sample with a biotinylated mammalian anti-human IgG that recognizes and binds non-covalently to all human antibodies in the sample. In another example, all of the antibodies in a sample are biotinylated through the covalent binding of biotin to the antibodies.
There is a need for an assay for a macromolecular analyte such as an antibody that does not utilize a reagent that binds to all macromolecular substances in a sample. The assay should minimize the number of reagents necessary to measure the macromolecular analyte of interest that is present in a sample.